SEATTLE -- The soldiers who reported to Staff Sgt. Calvin Gibbs paint a monstrous picture: He killed Afghan civilians for sport, they say, and encouraged others to do the same. He collected fingers of the dead, plotted against his own men and found it amusing to slaughter animals with his assault rifle.

Gibbs will get a chance to contest that portrait Tuesday during a military hearing at Joint Base Lewis-McChord south of Seattle on charges that include murder, dereliction of duty and trying to impede an investigation.

The Article 32 hearing is similar to a civilian grand jury proceeding, with a military judge looking into charges to see if there is enough evidence to send the case to a court martial.

Gibbs insists all of the deaths were appropriate engagements, according to his lawyer, Phillip Stackhouse, who declined to comment further.

The 25-year-old from Billings, Mont., is the highest-ranking of five soldiers charged in the murders of three civilians during patrols in Kandahar Province this year in what has emerged as one of the most gruesome cases of the Afghan war.

Seven other soldiers -- including two from Oregon -- have been charged in connection with the conspiracy or with attempting to cover it up. The two soldiers from Oregon are Staff Sgt. Robert Stevens of Portland and Cpl. Emmitt Quintal of Weston.

"(Gibbs) liked to kill," said Spc. Adam Winfield, who said he tried to blow the whistle on the alleged murder plot before taking part in the final killing. "He manipulated a lot of us into doing what he wanted us to do."

Gibbs arrived in the platoon late last year and soon began telling his subordinates how easy it would be to kill civilians, some soldiers told investigators in statements reviewed by the AP.

Gibbs reportedly spoke of getting away with killing a family when he served in Iraq -- a claim investigators are still looking into.

He devised scenarios under which he could kill Afghan civilians, the soldiers said, suggesting in one case that if he and his men came across someone in a village flagged as Taliban-influenced, they could toss a grenade and claim they had been responding to a threat.

Gibbs also illicitly collected weapons -- including an AK-47 and a rocket-propelled grenade -- which he could plant on the bodies of dead civilians to make them appear to be combatants, the soldiers said.

In addition to the killings, Gibbs and some of his men fired at -- but missed -- two unarmed farmers during a patrol in late March, investigators were told.

Gibbs falsely reported that they shot at three combatants, one armed with a rocket launcher, according to Staff Sgt. Robert G. Stevens, of Portland, Ore., who said he took part in the attack but tried to miss the farmers.

"I was extremely thankful to find out that we had not killed or wounded either of those two individuals, and I regret not trying to stop Staff Sgt. Gibbs from trying to kill innocent people," he said in a sworn statement.

Stevens, Gibbs and four other soldiers are charged with conspiring to commit aggravated assault in that incident.

The probe of the killings started after a witness in a drug investigation, Pvt. 1st Class Justin Stoner, reported being badly beaten by a group of soldiers led by Gibbs.

Stoner said Gibbs and the other central figure in the case, Spc. Jeremy Morlock, of Wasilla, Alaska, later returned to his room, where Gibbs laid a set of severed fingers on the floor as Morlock warned him not to rat.

"I believe he has no regard for any life in general," Stoner said of Gibbs. "I have watched him slaughter animals with his M-4 and finding it amusing is just completely wrong."

After the beating, Stoner told investigators he believed Morlock had three unjustified kills.

The first was in January. Morlock said in extensive statements to investigators that it happened a few weeks after Gibbs gave him an illicit grenade and told him he should carry out the scenario they had discussed.

Morlock said he tossed the grenade at a man in a field as another soldier, Pvt. 1st Class Andrew Holmes, of Boise, Idaho, shot; Holmes says he had no knowledge of any plot to kill civilians.

Winfield sent messages home to his parents in Cape Coral, Fla., after that killing, telling them that his colleagues had murdered a civilian. They were urging him to get one of his own, he said, and he was being threatened to keep quiet.

Winfield's father called several phone numbers at Lewis-McChord that day. He said he told a sergeant about his son's situation and urged the Army to intervene, and his phone records reflect a 12-minute conversation with someone at the base.

Gibbs is accused of killing a civilian in February, a week after Winfield's father made the calls, and dropping an AK-47 by the victim's body to make it appear he was armed. Spc. Michael Wagnon is also accused of participating in that killing, but denies involvement.

In the third killing, in May, Gibbs is accused of tossing a grenade at a civilian as Morlock and Winfield shot. They told investigators the victim posed no threat; Winfield, who said he felt pressured by Gibbs, called it "the worst thing I've ever done in my life."

Morlock claimed to be deathly afraid of Gibbs even as he participated in killings: "He's crazy. There's something wrong with that guy," he told investigators in a videotaped interrogation.

But other soldiers from the platoon said Gibbs was well-liked and that his competence and experience likely saved lives.

"Staff Sgt. Gibbs from what I have seen is a charismatic individual and a group leader both on patrol and off, one of the best (noncommissioned officers) I've had the pleasure of working with in my military career," said Spc. Adam W. Kelly of Montesano, Wash.